Affinage

ZCCHC8

Zinc finger CCHC domain-containing protein 8 · UniProt Q6NZY4

Length
707 aa
Mass
78.6 kDa
Annotated
2026-06-11
11 papers in source corpus 8 papers cited in narrative 9 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 6/6 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

ZCCHC8 is the scaffold subunit of the nuclear exosome targeting (NEXT) complex, coupling RNA substrate recognition to the catalytic machinery that degrades or matures aberrant and noncoding nuclear RNAs (PMID:29844170, PMID:27905398). A proline-rich segment of ZCCHC8 directly engages the RNA-recognition motif of RBM7, incorporating it into NEXT, while structural mimicry of the splicing factor SAP145 by this motif allows RBM7 to partition between NEXT and spliceosomal components (PMID:27905398). Through a bipartite C-terminal interaction with the MTR4 helicase core, ZCCHC8 directly stimulates MTR4 helicase and ATPase activities, with RBM7 association further enhancing activity on uridine-rich and polyadenylated substrates (PMID:29844170). Functionally, ZCCHC8 directs 3' end maturation and degradation of diverse RNA classes by the nuclear RNA exosome, including telomerase RNA, intronless replication-dependent histone mRNAs, and LINE1 retrotransposon transcripts (PMID:31488579, PMID:31747613). Loss of ZCCHC8 causes accumulation of genomically extended telomerase RNA at the expense of mature TR, and heterozygous loss-of-function produces TR insufficiency in human carriers and mice (PMID:31488579); a localization-disrupting mutation lowers DKC1 and RTEL1 expression and shortens telomeres, linking ZCCHC8 nuclear localization to telomere maintenance (PMID:39256642). Beyond RNA turnover, ZCCHC8-mediated LINE1 degradation shapes the chromatin landscape during early development and spermatogenesis (PMID:31747613, PMID:39758125), and ZCCHC8 is directly phosphorylated by GSK-3 (PMID:16263084).

Mechanistic history

Synthesis pass · year-by-year structured walk · 9 steps
  1. 2005 Medium

    Established ZCCHC8 as a nuclear protein physically associated with RNA processing/degradation machinery and a direct kinase substrate, providing the first functional context before NEXT was defined.

    Evidence In vitro GSK-3 kinase assay, cellular GSK-3 inhibition, and co-IP with RNA-binding proteins

    PMID:16263084

    Open questions at the time
    • Specific phosphosites and the functional consequence of GSK-3 phosphorylation not defined
    • Identity of the associated RNA-processing partners not resolved at molecular level
  2. 2016 High

    Resolved how RBM7 is recruited into NEXT, showing ZCCHC8 acts as the structural bridge for substrate-recognition subunits.

    Evidence 2.0 Å crystal structure of the ZCCHC8 proline-rich segment bound to the RBM7 RRM, with domain mapping and in vitro binding

    PMID:27905398

    Open questions at the time
    • Does not address how the assembled complex selects in vivo RNA substrates
    • Functional consequence of the SAP145 mimicry / spliceosome crosstalk not tested in cells
  3. 2018 High

    Defined the catalytic coupling of NEXT, showing ZCCHC8 directly activates the exosome helicase rather than merely tethering it.

    Evidence Crystal structure of the ZCCHC8 C-terminal domain bound to the MTR4 helicase core, with reconstituted in vitro helicase/ATPase assays and mutagenesis

    PMID:29844170

    Open questions at the time
    • In vitro substrate preferences may not capture full physiological substrate range
    • How ZCCHC8 stimulation is regulated in the cell is unknown
  4. 2019 High

    Connected the molecular machinery to physiology, establishing ZCCHC8 as required for telomerase RNA 3' end maturation and as a disease-relevant cause of TR insufficiency.

    Evidence Human linkage/mutation carriers, Zcchc8-null mice, knockout cells, and RNA maturation assays

    PMID:31488579

    Open questions at the time
    • Mechanism by which extended TR is selectively recognized vs other substrates not dissected
    • Clinical penetrance/spectrum from heterozygous loss not fully mapped
  5. 2019 Medium

    Generalized ZCCHC8 function beyond telomerase RNA, showing it mediates 3' end processing of multiple low-abundance RNA classes.

    Evidence Zcchc8-null mouse transcriptome and RNA 3' end sequencing of histone and cilia-component RNAs

    PMID:31488579

    Open questions at the time
    • Single-lab transcriptomic readout
    • Direct vs indirect effects on each RNA class not separated
  6. 2019 Medium

    Identified a developmental role through targeted degradation of LINE1 transcripts, linking RNA surveillance to chromatin state and developmental potency.

    Evidence Zcchc8 knockout mice, ESC depletion, RNA quantification, chromatin accessibility assays, developmental phenotyping

    PMID:31747613

    Open questions at the time
    • Whether LINE1 effects are entirely exosome-dependent not established
    • Single-lab phenotype
  7. 2024 Medium

    Demonstrated that nuclear localization of ZCCHC8 is functionally required for telomere maintenance, tying a specific mutation to downstream telomere-pathway gene expression.

    Evidence Whole exome/Sanger sequencing of a family, subcellular localization assay, DKC1/RTEL1 expression and telomere length measurement

    PMID:39256642

    Open questions at the time
    • Single family, single lab
    • Mechanism linking mislocalization to reduced DKC1/RTEL1 expression unresolved
  8. 2024 Medium

    Extended the LINE1-surveillance role to meiosis, showing ZCCHC8 loss derepresses young LINE1 and alters histone marks, impairing spermatogenesis.

    Evidence Zcchc8 knockout mouse, RNA-seq, ChIP-seq for H3K9me3 and H3K4me3, spermatogenesis phenotyping

    PMID:39758125

    Open questions at the time
    • Causal link between RNA derepression and the observed histone changes not fully separated
    • Single-lab study
  9. 2025 Low

    Proposed a role for NEXT/ZCCHC8 in 3D genome organization via ncRNA degradation affecting cohesin and enhancer-promoter contacts.

    Evidence ChIP-seq chromatin recruitment, NEXT depletion with RNA-seq, and chromatin conformation capture (preprint)

    PMID:bio_10.1101_2025.08.25.671287

    Open questions at the time
    • Preprint, not peer-reviewed; primary focus on MTR4 rather than ZCCHC8
    • Indirect link between ncRNA degradation and cohesin/3D contacts
    • ZCCHC8-specific contribution not isolated

Open questions

Synthesis pass · forward-looking unresolved questions
  • How ZCCHC8 substrate selectivity is governed across its diverse RNA targets, and how post-translational regulation (e.g. GSK-3 phosphorylation) and chromatin recruitment integrate with NEXT activity, remain open.
  • No unified model of substrate discrimination among TR, histone mRNAs, and LINE1
  • Functional consequence of GSK-3 phosphorylation undefined
  • Chromatin-recruitment mechanism unconfirmed in peer-reviewed work

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0003723 RNA binding 3 GO:0060090 molecular adaptor activity 2 GO:0098772 molecular function regulator activity 1
Localization
GO:0005634 nucleus 2 GO:0005694 chromosome 1
Pathway
R-HSA-8953854 Metabolism of RNA 4
Partners
GSK-3MTR4RBM7
Complex memberships
NEXT (nuclear exosome targeting) complex

Evidence

Reading pass · 9 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2018 Crystal structure of the ZCCHC8 C-terminal domain bound to the MTR4 helicase core reveals a bipartite interaction that is distinct from yeast exosome cofactors Trf4p/Air2p; this interaction stimulates MTR4 helicase and ATPase activities. RBM7 association with NEXT further enhances MTR4 helicase activity, with uridine-rich substrates preferred by RBM7 and polyadenylated 3' ends optimal for full activity. Crystal structure determination, in vitro helicase/ATPase assays, domain mapping, mutagenesis Proceedings of the National Academy of Sciences of the United States of America High 29844170
2016 A proline-rich segment of ZCCHC8 serves as the direct interaction site for the RNA-recognition motif (RRM) of RBM7, as revealed by crystal structure at 2.0 Å resolution, defining how RBM7 is incorporated into the NEXT complex. The same ZCCHC8 proline-rich motif shares structural similarity with splicing factor SAP145, allowing RBM7 to interact with both NEXT and spliceosomal components. Crystal structure (2.0 Å), domain mapping, in vitro binding assays Nature communications High 27905398
2019 ZCCHC8 associates with telomerase RNA (TR) and is required for its 3' end maturation; loss of ZCCHC8 causes accumulation of genomically extended TR at the expense of mature TR, consistent with a role in mediating TR 3' end targeting to the nuclear RNA exosome. Heterozygous loss-of-function of ZCCHC8 causes TR insufficiency in both human mutation carriers and heterozygous Zcchc8-null mice. Genome-wide linkage, ZCCHC8 knockout cells, Zcchc8-null mouse model, RNA analysis (TR maturation), association studies Genes & development High 31488579
2019 Zcchc8-null mice show accumulation and 3' end misprocessing of low-abundance RNAs including intronless replication-dependent histone mRNAs and cilia-component RNAs, demonstrating that nuclear exosome targeting via ZCCHC8 is an essential 3' end maturation mechanism shared across these RNA classes. Zcchc8-null mouse model, transcriptome analysis, RNA 3' end sequencing Genes & development Medium 31488579
2019 Zcchc8 is required for degradation of LINE1 retrotransposon transcripts in mouse early embryos and embryonic stem cells; Zcchc8-deficient ESCs exhibit proliferation abnormalities and reduced developmental potency, and maternal Zcchc8-depleted oocytes show higher chromatin accessibility and developmental defects, establishing a Zcchc8-mediated RNA degradation mechanism targeting LINE1. Zcchc8 knockout mouse, ESC depletion, RNA quantification, chromatin accessibility assays, developmental phenotyping Cell reports Medium 31747613
2005 Zcchc8 is directly phosphorylated by GSK-3 in vitro, and GSK-3 inhibition prevents Zcchc8 phosphorylation in vivo. Zcchc8 is a nuclear protein that interacts with RNA processing/degradation proteins. In vitro kinase assay with GSK-3, GSK-3 inhibitor treatment in cells, immunoprecipitation with RNA-binding proteins Biochemical and biophysical research communications Medium 16263084
2024 A novel ZCCHC8 mutation (p.P410A) disrupts nucleocytoplasmic localization of ZCCHC8, which further decreases expression of DKC1 and RTEL1 and reduces telomere length, linking ZCCHC8 nuclear localization to telomere maintenance. Whole exome sequencing, Sanger sequencing, subcellular localization assay, gene expression analysis, telomere length measurement Molecular medicine (Cambridge, Mass.) Medium 39256642
2024 Loss of ZCCHC8 during spermatogenesis results in upregulation of young LINE1 (L1Md_A) subfamilies in spermatogonial stem cells and pachytene spermatocytes, accompanied by reduced H3K9me3 in SSC and elevated H3K4me3 in pachytene spermatocytes at L1 loci, contributing to impaired chromatin condensation and delayed meiotic progression. Zcchc8 knockout mouse, RNA-seq, ChIP-seq for H3K9me3 and H3K4me3, spermatogenesis phenotyping National science review Medium 39758125
2025 Chromatin recruitment mapping shows ZCCHC8 (NEXT) associates with sites of enhancer-promoter interactions. Depletion of NEXT induces accumulation of ncRNAs (eRNAs and PROMPTs) and increases cohesin levels at those sites, suggesting NEXT-mediated ncRNA degradation influences cohesin binding and 3D enhancer-promoter contacts. ChIP-seq (chromatin recruitment), NEXT depletion, RNA-seq, chromatin conformation capture (3C/Hi-C) bioRxivpreprint Low bio_10.1101_2025.08.25.671287

Source papers

Stage 0 corpus · 11 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2019 ZCCHC8, the nuclear exosome targeting component, is mutated in familial pulmonary fibrosis and is required for telomerase RNA maturation. Genes & development 105 31488579
2018 Structural basis for MTR4-ZCCHC8 interactions that stimulate the MTR4 helicase in the nuclear exosome-targeting complex. Proceedings of the National Academy of Sciences of the United States of America 57 29844170
2016 Structure of the RBM7-ZCCHC8 core of the NEXT complex reveals connections to splicing factors. Nature communications 43 27905398
2019 Nuclear Exosome Targeting Complex Core Factor Zcchc8 Regulates the Degradation of LINE1 RNA in Early Embryos and Embryonic Stem Cells. Cell reports 40 31747613
2016 Identification of ZCCHC8 as fusion partner of ROS1 in a case of congenital glioblastoma multiforme with a t(6;12)(q21;q24.3). Genes, chromosomes & cancer 33 27121553
2005 Zcchc8 is a glycogen synthase kinase-3 substrate that interacts with RNA-binding proteins. Biochemical and biophysical research communications 21 16263084
2020 A COMMON PITUITARY AUTOANTIBODY IN TWO PATIENTS WITH IMMUNE CHECKPOINT INHIBITOR-MEDIATED HYPOPHYSITIS: ZCCHC8. AACE clinical case reports 12 32671216
2024 A new variant in the ZCCHC8 gene: diverse clinical phenotypes and expression in the lung. ERJ open research 7 38375433
2018 A novel co-existing ZCCHC8-ROS1 and de-novo MET amplification dual driver in advanced lung adenocarcinoma with a good response to crizotinib. Cancer biology & therapy 6 30095326
2024 ZCCHC8 p.P410A disrupts nucleocytoplasmic localization, promoting idiopathic pulmonary fibrosis and chronic obstructive pulmonary disease. Molecular medicine (Cambridge, Mass.) 5 39256642
2024 Core factor of NEXT complex, ZCCHC8, governs the silencing of LINE1 during spermatogenesis. National science review 1 39758125

Missed literature

Know a paper Affinage missed for ZCCHC8? Flag it for the maintainers and the community.

No submissions yet.